The role of cell membrane strain in sonoporation characterised by microfluidic-based single-cell analysis

In the present study we have investigated the sonoporation dynamics in a single cell using a novel microfluidic-based approach. Our methodology has successfully addressed the biophysical mechanisms underlying US-induced cell membrane sonoporation by performing in situ measurement of localised cell membrane deformation, and simultaneous quantification of both intracellular calcium concentration ([Ca2+]i) and transmembrane transfer of extracellular membrane-impermeable probes. We have highlighted novel aspects of microbubble-cluster dynamics combined with localised cell membrane strain, which could be responsible for membrane permeabilisation and transmembrane pore formation correlated with the transduction of intracellular biochemical signals (i.e. [Ca2+]i influx) as a result of microbubble-cell interaction

The role of acoustofluidics in targeted drug delivery

With the fast development of acoustic systems in clinical and therapeutic applications, acoustically driven microbubbles have gained a prominent role as powerful tools to carry, transfer, direct, and target drug molecules in cells, tissues, and tumors in the expanding fields of targeted drug delivery and gene therapy. The aim of the present study is to establish a biocompatible acoustic microfluidic system and to demonstrate the generation of an acoustic field and its effects on microbubbles and biological cells in the microfluidic system. The acoustic field creates non-linear oscillations of the microbubble-clusters, which results in generation of shear stress on cells in such microsystems. This effectively helps in delivering extracellular probes in living cells by sonoporation. The sonoporation is investigated under the combined effects of acoustic stress and hydrodynamic stress during targeted drug and gene delivery

Enhancement of static incubation time in microfluidic cell culture platforms exploiting extended air–liquid interface

Microfluidics based cell culture applications have facilitated the study of cellular dynamics at the single entity level. Yet, long term versions of such applications in a static framework suffer from the fast exhaustion of available oxygen, dissolved in the limited media volume available per cell, within the microconfined environment. In order to circumvent such drawbacks, we have improvised a microfluidic cell culture platform for prolonged sustenance of adherent mammalian cells by formation of an air–liquid interface through functionalizing inner surfaces of a polydimethylsiloxane (PDMS) based microdevice. We have demonstrated an augmented static incubation time for different cell lines using this approach

Effect of dispersion on the diffusion zone in two-phase laminar flows in microchannels

Aim of the present work is to investigate the reaction–diffusion process of a two species system under laminar flow in a T-shaped microchannel. A zone formed at the interface between the aqueous solutions of these two species is affected by advection and diffusion. Through theoretical analyses and experimental results, the effect of dispersion has been shown to influence this diffusion zone. We have defined a parameter called effective diffusivity, to account for the dispersion effects and observed it to be a function of the channel Peclet number. In the limiting case of low Peclet number, this parameter is constant and turns out to be equal to the molecular diffusivity. We have also related effective diffusivity and the dispersion coefficient through scaling estimates